Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full burden. It does disclose that the tool provides real-time quotes with daily highs/lows and volume, which is useful. However, it omits details such as whether a single symbol is required (though the schema shows this), any rate limits, or response structure nuances. The behavioral description is adequate but not rich.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two sentences and front-loads the core action. The phrase 'with the Stock Index Quote API' is slightly redundant, but the text is concise and avoids unnecessary verbosity.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple one-parameter tool with no output schema, the description explains the type of data returned (price changes, highs/lows, volume). It does not detail the exact return format, but the high-level description is sufficient given the tool's simplicity.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema covers the only parameter 'symbol' with a description and example, so coverage is 100%. The tool description adds no additional meaning beyond what the schema already provides, so the baseline of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool accesses real-time stock index quotes and lists the key metrics it returns. However, it does not explicitly differentiate this tool from sibling tools like getIndexQuotes or getIndexShortQuote, relying on the tool name to imply single-quote retrieval.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides no guidance on when to use this tool versus alternatives such as getIndexQuotes or getIndexShortQuote. There is no mention of use cases, exclusions, or preferred scenarios, leaving the agent to infer from the name alone.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.